Chemical process

ABSTRACT

Process for the preparation of herbicidally active substituted cyclohexan-1,3,5-triones which comprises either 
     (a) reacting a compound of formula (II) ##STR1##  wherein R 2 , R 3 , R 4  and R 5  are, for example, hydrogen or C 1  -C 4  alkyl with a compound of formula (III): 
     
         R.sup.1 COCN                                               (III) 
    
      wherein R 1  is optionally substituted aryl in the presence of a base and a Lewis acid; or 
     (b) reacting a compound of formula (VI) ##STR2##  with a compound of formula (X) ##STR3##  in the presence of a Lewis acid; or (c) where R 2 , R 3 , R 4  and R 5  are the same, reacting a compound of formula (XI) ##STR4##  with a compound of formula R 2  X&#39; in the presence of a base, wherein X&#39; is a leaving group.

This is a division of U.S. application Ser. No. 17/164,963, filed Mar.7, 1988, now U.S. Pat. No. 4,912,262.

The present invention relates to a process for the preparation ofcertain herbicidally active substituted cyclohexan-1,3,5-triones.

Copending European patent application No. EP-A-252298 describes andclaims a series of 2-benzoyl-1,3,5-cyclohexanetriones, their use asherbicides and a route for their preparation. The applicants have nowfound an alternative route to these and some related compounds.

According to the present invention there is provided process forpreparing a compound of formula (I): ##STR5## or a salt, acylate orsulphonate derivative thereof; wherein R¹ is an optionally substitutedaryl group, R², R³, R⁴ and R5 are selected from hydrogen, C₁₋₄ alkyl,C₁₋₄ alkanoyl or --CO₂ R^(a) wherein R^(a) is C₁₋₄ alkyl or R² and R³ orR⁴ and R⁵ together with the carbon atom to which they are attached forma C₃₋₆ cycloalkyl ring, provided that at least R² and R³ or R4 and R5are not both hydrogen and that not more than two of R², R³, R⁴ and R⁵are C₁₋₄ alkanoyl or --CO₂ R^(a) ; which process comprises reacting acompound of formula (II) : ##STR6## wherein R², R³, R⁴ and R⁵ are asdefined in relation to formula (I) with a compound of formula (III):

    R.sup.1 COCN                                               (III)

wherein R¹ is as defined in relation to formula (I) in the presence of abase and a Lewis acid.

Suitable bases include both organic bases such as tertiary amines andinorganic bases such as alkali metal carbonates and phosphates. Suitabletertiary amines include trialkylamines such as triethylamine,trialkanolamines such as triethanolamine, and pyridine. Switableinorganic bases include potassium carbonate and trisodium phosphate.Suitable Lewis acids are zinc chloride and aluminium trichloride,preferably zinc chloride. The reaction is carried out in an organicsolvent such as acetonitrile or methylene chloride and at moderatetemperatures of from -20° C. to +90° C. Suitably both the zinc chlorideand the base are present in a slight molar excess with respect to thecompounds of formula (II) and (III).

Compound of formula (I) can exist in a number of tautomeric forms, forexample: ##STR7## wherein R¹, R², R³, R⁴ and R⁵ are as defined inrelation to formula (I). When one or more of R² R³, R⁴ and R⁵ arehydrogen, further tautomers exist.

Compounds of formulae (III) are either known compounds or they can beprepared from known compounds by conventional methods.

Compounds of formula (II) wherein R², R³ are methyl and R⁴ and R⁵ aremethyl or hydrogen and their preparation are described by Riedl andRisse (Justus Liebiqs Annalen der Chemie, 1954, 585, 209).

Compounds of formula (II) wherein R², R³, R⁴ and R⁵ are the same and areC₁₋₄ alkyl in particular methyl can be prepared by the followingreaction Scheme A. ##STR8## wherein X' is a leaving group such ashalogen, in particular iodide. Suitable reaction conditions will beapparent by analogy with the above-mentioned publication. For example,one suitable base for use in the first step in Scheme A is sodiummethoxide in methanol. A suitable acid for use in second step of SchemeA is an inorganic acid such as hydrochloric acid.

By adjusting the conditions in the first step of the process, it may bepossible to obtain compounds of formula j (II) wherein R⁴ and/or R⁵ arehydrogen. Alternatively compounds of formula (II) can be prepared usingthe methods described by Murin et al (Chem. Ber. 1959, 92, 2033) ormethods analogous thereto. In this way compounds of formula (II) areprepared by cyclisation of a compound of formula (IV): ##STR9## in thepresence of a base such as sodium methoxide an organic solvent such asmethanol. Compounds of formula (IV) can be prepared as outlined inScheme B. ##STR10##

Precise reaction conditions for each step in Scheme B will depend uponthe particular compounds involved and can be determined by routineprocedures and the relevant literature.

Compounds of formula (V) can be prepared by the reaction of compounds offormula (VII): ##STR11## with a compound of formula R⁴ X' and optionallythereafter with a compound of formula R⁵ X' in the presence of a basesuch as sodium methoxide in an organic solvent such as methanol, whereinR⁴, R⁵ and X' are as hereinbefore

When R⁴ and R⁵ are the same, then the reaction can be carried out in asingle step. By controlling the reaction conditions, the extent of thereaction (i.e. whether one or both hydrogen atoms on the methylene arereplaced by R⁴) can be determined.

Compounds of formula (VII) can be prepared by reaction of a compound offormula (VIII): ##STR12## wherein R² and R³ are as hereinbefore definestrong base such as lithium diisopropyl-amide and (b) CH₃ O₂ CCl underconventional reaction conditions.

Compounds of formula (VIII) can be prepared by reacting a compound offormula (IX): ##STR13## with a compound of formula R² X' in the presenceof a base; and optionally thereafter R³ X' wherein R², R³ and X' arehereinbefore defined, as described above for the reaction of thecompound of formula (VII).

Alternatively in a further aspect of the invention compounds of formula(I) can be prepared by reacting a compound of formula (VI) as set out inScheme B with a compound of formula (X): ##STR14## wherein R¹ is ashereinbefore defined, in the presence of a Lewis acid such as aluminiumtrichloride.

Reactions of this type are described by Merenyi and Nilson (Acta Chem.Scand, 1963, 17, 1801 and Acta Chem. Scand, 1964, 18, 1368).

Compounds of formula (X) are known compounds or hey can be prepared fromknown compounds by conventional methods.

Furthermore, in yet another aspect of the invention compounds of formula(I) wherein R², R³, R⁴ and R⁵ are the same, can also be prepared byreacting a compound of formula (XI): ##STR15## with a compound offormula R² X' in the presence of a base, wherein R¹, R² and X' are ashereinbefore defined.

Suitable bases for use in the reaction are strong bases such as sodiummethoxide.

The reaction is suitably carried out in an organic solvent such asmethanol at temperatures of from 0 to 100° C.

When the compound of formula (I) contains a free hydroxy group, it maybe derivatised to form salts, in particular agriculturally acceptablesalts, acylates or sulphonates.

Suitable agriculturally acceptable salts include salts such as sodium,potassium, calcium and quaternary ammonium salts.

Suitable acylate derivatives are compounds wherein the OH moiety hasbeen converted to a group of formula --OCOR⁶ wherein R⁶ is alkyl havingfor example from 1 to 6 carbon atoms, or aryl such as phenyl.

Suitable optionally substituted aryl groups R¹ include optionallysubstituted phenyl.

Suitable optional substituents for the group R¹ are up to three groupsselected from halogen such as fluorine, chlorine and bromine; C₁₋₄alkyl; C₁₋₄ alkoxy; halo (C₁₋₄) alkoxy such as trifluoromethoxy andtetrafluoroethoxy; cyano; nitro; C₁₋₄ haloalkyl such as trifluoromethyl;R⁷ SO_(n) - where n is 0, 1 or 2 and R⁷ is Cl-4alkyl optionallysubstituted with halogen or cyano, phenyl or benzyl; NR⁸ R⁹ wherein R⁸and R⁹ are independently hydrogen or C₁₋₄ alkyl; R¹⁰ CO- where R¹⁰ isC₁₋₄ alkyl or C₁₋₄ alkoxy; or SO₂ NR⁸ R⁹ where

Preferred substituents for the group R¹ are one or two groups selectedfrom halogen, haloalkyl in particular trifluoromethyl, R⁷ SO₂ such asMeSO₂ --, nitro or cyano.

The group R¹ may, for example, contain one substituent in theortho-position on the ring or it may contain substituents in both theortho- and para-positions on the ring.

Preferably R¹ is substituted phenyl.

A suitable alkanoyl group for R², R³, R⁴ and R⁵ is acetyl.

Preferably only one of R², R³, R⁴ and R⁵ is either alkanoyl or --CO₂R^(a).

Most preferably R², R³, R⁴ and R⁵ are C₁₋₄ alkyl in particular methyl.

Examples of compounds of formula (I) are set out in Table I.

                  TABLE I                                                         ______________________________________                                         ##STR16##                                                                    COMPOUND                                                                      NO.        R.sup.2                                                                              R.sup.3  R.sup.4                                                                            R.sup.5                                                                              R.sup.11                                                                           R.sup.12                          ______________________________________                                        1          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             Cl   H                                 2          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             Cl   Cl                                3          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             Br   H                                 4          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             F    H                                 5          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             CF.sub.3                                                                           H                                 6          CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           CH.sub.3                                                                             H    H                                 ______________________________________                                    

Certain compounds of formula (I) are not described in European PatentApplication No. EP-A-252298 and these form another aspect of theinvention.

Yet further according to the invention there is provided a salt, acylateor sulphonate derivative of formula (I) or a compound of formula (IA)##STR17## wherein R¹³ is optionally substituted aryl and one or twogroups R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are C₁₋₄ alkanoyl or CO₂ R⁹ wherein R⁹ isC₁₋₄ alkyl and the remainder are selected from hydrogen or C₁₋₄ alkyl;or R¹³ is unsubstituted aryl and R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are equivalent toR², R³, R⁴ and R⁵ as hereinbefore respectively; and tautomers thereof.

Compound 6 herein is an example of a compound of formula (IA).

Compounds of formula (IA) can also be prepared by rearrangement of acompound of formula (XII): ##STR18## wherein R¹³, R¹⁴, R¹⁵, R¹⁶ and R¹⁷are as defined in relation to formula (IA) in the presence of a cyanidesource and a moderate base.

The reaction is suitably carried out in an inert organic solvent such asacetonitrile and at a temperature of from 30° C. to 50° C., preferablyat from 20° C.-40° C.

Suitable cyanide sources are alkali metal cyanides such as sodium andpotassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4carbon atoms in the alkyl groups, such as acetone or methyl isobutylketone cyanohydrins; cyanohydrins of benzaldehyde or of C₂ -C₅ aliphaticaldehydes such as acetaldehyde, propionaldehyde, etc., cyanohydrins;zinc cyanide; tri(lower alkyl) silyl cyanides, notably trimethyl silylcyanide; and hydrogen cyanide itself.

A preferred cyanide source is acetone cyanohydrin.

The amount of the cyanide source employed is sufficient to catalyse thereaction, for example from 1-50 mole percent of the compound of formula(XII), preferably from 1 to 10 mole percent.

Suitable bases for use in the reaction are those described above for usein the reaction between the compound of formulae (II) and (III).

Suitably the base is used in an amount of from about 1 to about 4 molesper mole of compound of formula (II), preferably about 2 moles per mole.

Compounds of formula (XII) can be prepared by reacting a compound offormula (II) as hereinbefore defined with a compound of formula (XIII)

    R.sup.13 COX                                               (XIII)

wherein R13 is as defined in relation to formula (XII) and X is aleaving group in the presence of a base.

Suitable bases for use in the reaction are the moderate bases describedabove for use in the reaction of the compound of formula (II) with acompound of formula (III). A preferred base is triethylamine.

Suitable leaving groups X include halogen such as chlorine.

The reaction is suitably carried out in an inert organic solvent such asdichloromethane, methylene toluene, ethyl acetate or dimethylformamideat moderate temperatures of from 0° C. to 50° C., conveniently at roomtemperature.

Compounds of formula (XII) may also be prepared by reacting a compoundof formula (II) with an acid of formula (XIV):

    R.sup.1 CO.sub.2 H                                         (XIV)

wherein R¹ is as defined in relation to formula (I), in the presence ofa dehydrating agent and a basic organic catalyst.

Suitable dehydrating agents include dicyclohexylcarbodiimide (DCC) whichis employed in an amount of at least one molar equivalent to thecompounds of formulae (II) and (XIV).

Examples of suitable basic organic catalysts include4-dimethylaminopyridine (DMAP) and 4-pyrrolidinopyridine (PPY).

The reaction is suitably carried out in an inert organic solvent such asacetonitrile, dichloromethane or 1,2-dichloroethane. Moderatetemperatures for example from 0° C. to 40° C. can be employed,conveniently ambient temperature.

The salts, acylate or sulphonate derivatives of the compounds of formula(I) and compounds of formula (IA) are active as herbicides andtherefore, in a further aspect the invention provides a process forseverely damaging or killing unwanted plants which process comprisesapplying to the plants, or to the growth medium of the plants, aneffective amount of a salt, acylate or sulphonate derivative of formula(I) or a compound of formula (IA) as hereinbefore defined.

These novel compounds are active against a broad range of weed speciesincluding monocotyledenous and dicotyledonous species. They may showsome selectivity towards certain species.

The novel compounds may be applied directly to the plant (post-emergenceapplication) or to the soil before the emergence of the plant(pre-emergence application). However, the compounds are, in general,more effective when applied to the plant pre-emergence.

The novel compounds of the invention may be used on their own to inhibitthe growth of, severely damage, or kill plants but are preferably usedin the form of a composition comprising a compound of the invention inadmixture with a carrier comprising a solid or liquid diluent.

Therefore, in yet a further aspect the invention provides plant growthinhibiting, plant damaging, or plant killing compositions comprising anovel compound as hereinbefore defined and an inert carrier or diluent.

Compositions containing novel compounds of the invention include bothdilute compositions, which are ready for immediate use, and concentratedcompositions, which require to be diluted before use, usually withwater. Preferably the compositions contain from 0.01% to 90% by weightof the active ingredient. Dilute compositions ready for use preferablycontain from 0.01 to 2% of active ingredient, while concentratedcompositions may contain from 20 to 90% of active ingredient, althoughfrom 20 to 70% is usually preferred.

The solid compositions may be in the form of granules, or dustingpowders wherein the active ingredient is mixed with a finely dividedsolid diluent, e.g., kaolin, bentonite, kieselguhr, dolomite, calciumcarbonate, talc, powdered magnesia, Fuller's earth and gypsum. They mayalso be in the form of dispersible powders or grains, comprising awetting agent to facilitate the dispersion of the powder or grains inliquid. Solid compositions in the form of a powder may be applied asfoliar dusts.

Liquid compositions may comprise a solution or dispersion of an activeingredient in water optionally containing a surface-active agent, or maycomprise a solution or dispersion of an active ingredient in awater-immiscible organic solvent which is dispersed as droplets inwater.

Surface-active agents may be of the cationic, anionic, or non-ionictype. The cationic agents are, for example, quaternary ammoniumcompounds (e.g. cetyltrimethylammonium bromide). Suitable anionic agentsare soaps; salts or aliphatic mono ester of sulphuric acid, for examplesodium lauryl sulphate: and salts of sulphonated aromatic compounds, forexample sodium dodecylbenzenesulphonate, sodium, calcium, and ammoniumliqnosulphonate, butylnaphthalene sulphonate, and a mixture of thesodium salts of diisopropyl and triisopropylnaphthalenesulphonic acid.Suitable non-ionic agents are the condensation products of ethyleneoxide with fatty alcohols such as oleyl alcohol and cetyl alcohol, orwith alkylphenols such as octyl- or nonyl-phenol or octyl-cresol. Othernon-ionic agents are the partial esters derived from long chain fattyacids and hexitol anhydrides, for example sorbitan monolaurate; thecondensation products of the partial ester with ethylene oxide; and thelecithins.

The aqueous solutions or dispersions may be prepared by dissolving theactive ingredient in water or an organic solvent optionally containingwetting or dispersing agent(s) and then, when organic solvents are used,adding the mixture so obtained to water optionally containing wetting ordispersing agent(s). Suitable organic solvents include, for example,ethylene di-chloride, isopropyl alcohol, propylene glycol, diacetonealcohol, toluene, kerosene, methylnaphthalene, the xylenes andtrichloroethylene.

The compositions for use in the form of aqueous solutions or dispersionsare generally supplied in the form of a concentrate containing a highproportion of the active ingredient, and the concentrate is then dilutedwith water before use. The concentrates are usually required towithstand storage for prolonged periods and after such storage, to becapable of dilution with water to form aqueous preparations which remainhomogeneous for a sufficient time to enable them to be applied byconventional spray equipment. Concentrates conveniently contain 20-90%,preferably 20-70%, by weight of the active ingredient(s). Dilutepreparations ready for use may contain varying amounts of the activeingredient(s) depending upon the intended purpose; amounts of 0.01% to10.0% and preferably 0.1% to 2%, by weight of active ingredient(s) arenormally used.

A preferred form of concentrated composition comprising the activeingredient which has been finely divided and which has been dispersed inwater in the presence of a surface-active agent and a suspending agent.Suitable suspending agents are hydrophilic colloids and include, forexample, polyvinylpyrrolidone and sodium carboxymethylcellulose, and thevegetable gums, for example gum acacia and gum tragacanth. Preferredsuspending agents are those which impart thixotropic properties too, andincrease the viscosity of the concentrate. Examples of preferredsuspending agents include hydrated colloidal mineral silicates, such asmontmorillonite, beidellite, nontronite, hectorite, saponite, andsaucorite. Bentonite is especially preferred. Other suspending agentsinclude cellulose derivatives and polyvinyl alcohol.

The rate of application of the compounds of the invention will depend ona number of factors including, for example, the compound chosen for use,the identity of the plants whose qrowth is to be inhibited, theformulations selected for use and whether the compound is to be appliedfor foliage or root uptake. As a general guide, however, an applicationrate of from 0.005 to 20 kilograms per hectare is suitable while from0.1 to 10 kilograms per hectare may be preferred.

The compositions of the invention may comprise, in addition to one ormore compounds of the invention, one or more compounds not of theinvention but which possess biological activity. Accordingly in yet astill further embodiment the invention provides a herbicidal compositioncomprising a mixture of at least one herbicidal compound of formula (I)as hereinbefore defined with at least one other herbicide.

The other herbicide may be any herbicide not having the formula (I) or(IA). It will generally be a herbicide having a complementary action inthe particular application. For example it may be desirable in certaincircumstances to use the novel compound of the invention in admixturewith a contact herbicide. Examples of useful complementary herbicidesinclude:

A. benzo-2,1,3-thiadiazin-4-one-2,2-dioxides such as3-isopropylbenzo-2,1,3-thiadiazin-4-one-2,2-dioxide (bentazon);

phenoxy alkanoic

B. hormone herbicides, particularly the acids such as4-chloro-2-methylphenoxy acetic acid (MCPA),2-(2,4-dichlorophenoxy)propionic acid (dichlorprop),2,4,5-trichlorophenoxyacetic acid (2,4,5-T),4-(4-chloro-2-methylphenoxy)butyric acid (MCP8),2,4-dichlorophenoxyacetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyricacid (2,4-DB), 2-(4-chloro-2-methylphenoxy)propionic acid (mecoprop),and their derivatives (e.g. salts, esters and amides);

C. 3-[4-(4-halophenoxy)phenyl]-1,1-dialkylureas such as3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea.

D. Dinitrophenols and their derivatives (eq. acetates) such as2-methyl-4,6-dinitrophenol (DNOC 2-t-butyl-4,6-dinitrophenol (dinoterb),2-secbutyl-4,6-dinitrophenol (dinoseb) and its ester, dinoseb acetate;

E. dinitroaniline herbicides such asN',N'-diethyl-2,6-dinitro-4-trifluoromethyl-m-phenylenediamine(dinitramine), 2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline(trifluralin) and 4-methylsulphonyl-2,6-dinitro-N,N-dipropylaniline(nitralin); 1 F. phenylurea herbicides such asN'-(3,4-dichlorophenyl)-N,N-dimethylurea (diuron) andN,N-simethyl-N'-[3-(trifluoromethyl)phenyl]urea (flumeturon);

G. phenylcarbamoyloxyphenylcarbamates such as 3-methoxycarbonylamino]phenyl (3-methylphenyl)carbamate (phenmedipham) and3-[ethoxycarbonylamino]phenyl phenylcarbamate (desmedipham);

H. 2-phenylpyridazin-3-ones such as5-amino-4-chloro-2-phenylpyridazin-3-one (pyrazon);

I. uracil herbicides such as 3-cyclohexyl-5,6-trimethyleneuracil(lenacil), 5-bromo-3-sec-butyl-6-methyl-uracil (bromacil) and3-t-butyl-5-chloro-6-methyl-uracil (terbacil);

J. triazine herbicides such as2-chloro-4-ethylamino-6-(i-propylamino)-1,3,5-triazine (atrazine),2-chloro4,6-di(ethylamino)-1,3,5-triazine (simazine) and2-azido-4-(i-propylamino)-6-methylthio-1,3,5-triazine (aziprotryne);

K. 1-alkoxy-1-alkyl-3-phenylurea herbicides such as3(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron),3-(4-chlorophenyl)-1-methoxy-1-methylurea (monolinuron),3-(4-bromo-4-chlorophenyl)-1-methoxy-1-methylurea (chlorobromuron).

L. thiolcarbamate herbicides such as S-propyl dipropylthiocarbamate(vernolate);

M. 1,2,4-triazin-5-one herbicides such as4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazine-5-one (metamitron)and 4-amino-6-t-butyl-4,5-dihydro-3-methylthio-1,3,4-triazin-5-one(metribuzin);

N. benzoic acid herbicides such as 2,3,6-trichlorobenzoic acid(2,3,6-TBA), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and3-amino-2,5-dichlorobenzoic acid (chloramben);

O. anilide herbicides such asN-butoxymethyl-chloro2',6'-diethylacetanilide (butachlor), thecorresponding N-methoxy compound (alachlor), the correspondingN-i-propyl compound (propachlor), 3',4'-dichloropropionanilide(propanil) and 2-chloro-N-[pyrazol-1-ylmethyl]acet-2'-6'-xylidide(metazachlor);

P. dihalobenzonitrile herbicides such as 2,6-dichlorobenzonitrile(dichlobenil), 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) and3,5-diiodo-4-hydroxybenzonitrile (ioxynil);

Q. haloalkanoic herbicides such as 2,2-dichloropropionic acid (dalapon),trichloroacetic acid (TCA) and salts thereof;

R. diphenylether herbicides such as 4-nitrophenyl2-nitro-4-trifluoromethylphenyl ether (fluorodifen), methyl5-(2,4-dichlorophenoxy)-2-nitrobenzoate (bifenox),2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)benzoic acid (acifluorfen)and salts and esters thereof, 2-chloro-4-trifluoromethylphenyl3-ethoxy-4-nitrophenyl ether (oxyfluorfen) and5-(2-chloro-4-(trifluoromethyl)phenoxy)-N-(methylsulfonyl)-2-nitrobenzamide(fomesafen); and

S. phenoxyphenoxypropionate herbicides such as2-(4-(4'-trifluoromethylphenoxy)-phenoxy)-propionic acid methylester(trifop-methyl),2-(4-((5-trifluoromethyl)-2-(pyridinyl)oxy)phenoxypropanoic acid(fluazifop) and esters thereof,2-(4-((3-chloro-5-trifluoro-methyl)-2-pyridinyl)oxy)phenoxy)propanoicacid (haloxyfop) and esters thereof,2-(4-((6-chloro-2-quinoxalinyl)oxy)phenoxypropanoic acid (xylofop) andesters thereof; and

T. cyclohexanedione herbicides such as2,2-dimethyl-4,6-dioxo-5-(1-((2-propenyloxy)amino)-butylidine)cyclohexane carboxylic acid (alloxydim) and salts thereof,2-(1-ethoxyimino)butyl-5-(2-(ethylthio)-propyl)-3-hydroxy-2-cyclohexen-1-one(sethoxydim),2-(1-(3-chloroallyloxyimino)butyl)-5-(2-ethylthio-propyl)-3-hydroxycyclohex-2-enone (cloproxydim),2-(1-ethoxyimino)butyl)-3-hydroxy-5-thian-3-yl cyclohex-2-enone(cycloxydim); and

U. sulfonyl urea herbicides such as2-chloro-N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-aminocarbonyl)benzenesulphonamide (chlorosulfuron), methyl2((((4,6-dimethyl-2-pyrimidinyl)amino)carbonyl)amino)sulphonylbenzoicacid (sulfometuron),2-(((3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbonyl)amino)sulphonyl)benzoicacid (metsulfuron) and esters thereof;

V. imidazolidinone herbicides such as 2-(4,5-dihydro-4-V.isopropyl-4-methyl-5-oxoimidazol-2-yl)quinoline-3-carboxylic acid(imazaquin), methyl6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate and p-toluateisomer (AC 222293)

W. arylanilide herbicides such as1-methylethyl-N-benzoyl-N-(3-chloro-4-fluorophenyl)-L-alanine(flamprop-isopropyl), ethylN-benzoyl-N-(3,4-dichloro-phenyl)-DL-alaninate (benzoylprop-ethyl),N-(2,4-difluorophenyl)-2-(3-(trifluoromethyl)phenoxy)-3-pyridinecarboxamidediflufenican); and

X. amino acid herbicides such as N-(phosphonomethyl)-glycine(glyphosate) and DL-homoalanin-4-yl(methyl)phosphinic acid(phosphinothricin) and their salts and esters; and

Y. organoarsenical herbicides such as monosodium methanearsonate (MSMA);and

Z. miscellaneous herbicides including N,N-dimethyl-diphenylacetamide(diphenamid), N-(1-naphthyl)phthalamic acid (naptalam) and3-amino-1,2,4triazole, 2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuranmethanesulfonate (ethofumesate), 1,4-epoxy-p-meth-2yl 2-methylbenzylether (cinmethylin);

AA. Examples of useful contact herbicides include: bipyridyliumherbicides such as those in which the active entity is the1,1'-dimethyl-4,4'-dipyridylium ion (paraquat) and those in which theactive entity is the 1,1'-ethylene-2,2'-dipyridylium ion (diguat);

The following examples illustrate the invention.

Preparation 1 ##STR19##

Iodomethane (17.04g, 120 mmol) was added slowly to a solution ofanhydrous 2,4,6-trihydroxyacetophenone (3.72g, 20 mmol) and sodiummethoxide (Na (2.76g, 120 mmol) in MeOH (100 ml)). The reaction mixturewas then heated under relux for 4 hours. Excess iodomethane and methanolwere removed by concentration under reduced pressure to yield a yellowsolid, which was dissolved in water and acidified with 2M hydrochloricacid (100 ml), whereupon a cream precipitate formed. The product wasextracted with diethyl ether and the combined extracts washed with 20%w/v sodium sulphite solution. The aqueous sulphite washings werecautiously acidified with 2M hydrochloric acid to give a whiteprecipitate, which was extracted with diethyl ether. All of the diethylether extracts were combined, dried over anhydrous magnesium sulphate,filtered and concentrated in vitro to give an orange oil whichcrystallised on standing to orange needles. Recrystallisation from60°-80° C. bpt. petroleum ether afforded the tetra-methylatedacetophenone (i) (3.22g, 72%) as yellow needles, melting point 38-40° C.

NMR (60 MHz, CDCl₃): 1.30 (6H, s), 1.39 (6H, s), 2.54 (3H, s), 18.18(1H, s).

IR (nujol) : 1720 (strong), 1670 (strong), 1560 (strong, broad) 1170(medium) 1050 (strong) cm⁻¹.

Preparation 2 ##STR20##

To the tetramethylated acetophenone (i) (2.91g, 13.0 mmol) fromPreparation 1 was added 2M hydrochloric acid (100 ml). The mixture washeated under reflux, whence enough ethanol was added to dissolveremaining solid. Heating was continued for 32 hours, during which timeconcentrated hydrochloric acid (50 ml) was added portion wise. Thesolution was allowed to cool and the yellow plates formed were filteredoff (1.33q, 57%), melting point 184-185° C.

NMR (60 MHz, CDC13) : δ1.7 (12H, s), 5.86 (1 (enolic proton broad - notobserved)

IR (nujol) : 2550-2750 (broad), 1710 (strong), 1620 (strong), 1540(strong), 1340 (weak), 1005 (strong), 1180 (strong), 1020 (medium) cm⁻¹.m.s. : M⁺ 182.

Preparation 3 ##STR21##

The reaction was carried out under Argon. Cuprous cyanide (5.0g, 56mmol) and anhydrous sodium iodide (15.6g, 104 mmol) were stirred for 2minutes with anhydrous acetonitrile (100 ml).

The resulting solution was mixed with o-chlorobenzoyl chloride (9.15g,52.3 mmol) whereupon an orange precipitate formed. The mixture wasstirred f-or 30 minutes at room temperature, filtered and concentratedin vacuo. The residue was taken up in dichloromethane and the resultingprecipitate was filtered off. Concentration in vacuo gave a yellow oilwhich crystallised on standing. Recrystallisation from 60° -80° C.b.p.t. petroleum ether qave o-chlorobenzoyl cyanide as white crystals(7.18q 85%), melting point 33° C.

IR (nujol) : 2200 (weak), 1680 (strong), 1580 (medium), 1230 (medium),1070 (weak), 970 (weak), 780 (weak), 740 (medium).

q.c. m.s. : M+165. (35 Cl)

EXAMPLE 1

This Example illustrates the preparation of Compound No. 1 in Table I.

The tetramethylated triketone (ii}(1.50q, 8.24 mmol), prepared asdescribed in Preparation 2, o-chlorobenzoyl cyanide (iii) (1.33q, 8.24mmol) prepared as described in Preparation 3, and anhydrous powderedzinc chloride (1.24q, 9.06 mmol) were combined in dry acetonitrile (10ml). Dry triethylamine (1.37 ml, 9.89 mmol) in anhydrous acetonitrile (5ml) was added dropwise to the mixture with cooling to -10° C. Thereaction mixture was allowed to reach room temperature, then heatedunder reflux for 3 hours. The mixture was then poured into 2Mhydrochloric acid (100 ml) and extracted with dichloromethane. Theorganic extracts were washed with 10% sodium carbonate solution (3×50ml) and the aqueous washings combined and acidified with 2M hydrochloricacid. The white precipitate was extracted with dichloromethane andconcentrated in vacuo to give a yellow solid. Recrystallisation from amethanol water mixture afforded cream crystals (1.05q, 40%), meltingpoint 71-72° C.

NMR (270 MHz, CDCl₃): δ(6H, s), 1.60 (6H, s), 7.4-7.6 (4H, complex),17.6 (1H, s).

IR (nujol) : 1720 (medium), 1680 (strong), 1560 (strong, broad), 1300(medium), 1030 (medium).

m.s. : MH⁺ 321. (³⁵ Cl)

Preparation 4 ##STR22##

The reaction was carried out under Argon. Cuprous cyanide (5.0g, 56.0mmol) and anhydrous sodium iodide (15.6g, 104 mmol) were stirred for 2minutes in anhydrous acetonitrile (100 ml). The resulting solution wasmixed with 2,4-dichlorobenzoyl chloride (10.96g, 52.3 mmol) whereupon anorange precipitate formed. The mixture was stirred for 30 minutes atroom temperature, filtered and concentrated in vacuo. The residue wastaken up in dichloromethane and the resulting precipitate was filteredoff. Concentration of the filtrate under reduce pressure gave a yellowsolid which was recrystallised from 60°-80° C. b.p.t. petroleum ether togive 2,4-dichlorobenzoyl cyanide as cream coloured crystals (8.36g,80%), melting point 73°-74° C.

NMR (60 MHz, CDC13) : δ7.5-8.1 (3H, complex). IR (nujol) : 220 (weak),1680 (stronq), 1580 (medium). g.c. m.s. : M⁺ 199 (³⁵ Cl)

EXAMPLE 2

This Example illustrates the preparation of Compound No. 2 in Table I.

The tetramethylated triketone (ii) (1.70g, 9.34 mmol,2,4-dichlorobenzoyl cyanide (iv) (1.84q, 9.34 mmol) and anhydrous,powdered zinc chloride (1.4g, 10.27 mmol) were combined in dryacetonitrile (10 ml). Triethylamine (1.56 ml, 11.21 mmol) in dryacetonitrile (5 ml) was added slowly to the mixture with cooling to -10°C. The reaction mixture was allowed to warm to room temperature, thenheated under reflux for 3 hours. The mixture was then poured into 2Mhydrochloric acid (100 ml) and extracted with dichloromethane. Theorganic extracts were washed with 10% sodium carbonate solution (3×50ml) and the aqueous washings combined and acidified with 2M hydrochloricacid.

The white precipitate was extracted with dichloromethane which was driedover magnesium sulphate, filtered and concentrated in vacuo to giveorange crystals in an orange oil. Trituration with 60°-80 ° C. b.p.t.petroleum ether, filtration and concentration of the filtrate in vacuoqave a pale orange oil, which crystallised on standing to a yellowsolid. Recrystallisation from an ethanol water mixture afforded creamcrystals (0.75g, 22.3%), melting point 61°-62° C.

NMR (270 MHz, CDCl₃): δ1.36 (6H, s), 1.56 (6H, s), 7.2-7.4 (3H,complex), 17.4 (1H, s).

IR 1720 (medium), 1680 (stronq), 1560 (broad, strong), 1200 (weak), 1040(weak) cm⁻¹. m.s. : M⁺ --Cl 319 (³⁵ Cl)

Preparation 5 ##STR23##

The reaction was carried out under Argon. Cuprous cyanide (6.52q, 72.8mmol) and anhydrous sodium iodide (20.25g, 135 mmol) were stirred for 2minutes in anhydrous acetonitrile (100 ml). The resulting solution wasmixed with o-bromo benzoyl chloride (15.0q, 68 mmol) whereupon an orangeprecipitate formed. The mixture was stirred for 30 minutes at roomtemperature, filtered and concentrated in vacuo. The residue was takenup in dichloromethane and the resulting precipitate was filtered off.Concentration of the filtrate under reduced pressure gave a yellowsolid. Recrystallisation from 60°-80° C. b.p.t. petroleum ether affordedo-bromo benzoyl cyanide as yellow crystals (7.14q, 50%), meltinq point64° C.

IR (nujol) : 2220 (weak), 1680 (strong), 1580 (medium) 1300 (medium),1230 (strong), 980 (medium), 780 (medium), 730 (strong) cm⁻¹.

EXAMPLE 3

This Example illustrates the preparation of Compound No. 3 in Table I.

The tetramethylated triketone (ii) (1.19g, 6.54 mmol), o-bromo-benzoylcyanide (v) (1.37g, 6.54 (mmol) and anhydrous, powdered zinc chloride(0.98g, 7.19 mmol) were combined in dry acetonitrile (10 ml).Triethylamine (1.09 ml, 7.85 mmol) in dry actonitrile (5 ml) was addedslowly to the mixture with cooling to -10° C. The reaction mixture wasallowed to warm to room temperature, then heated under reflux for 3hours. The mixture was then poured into 2M hydrochloric acid (100 ml)and extracted with dichloromethane. The organic extracts were washedwith 10% sodium carbonate solution (3×50 ml) and the carbonate washingswere combined and acidified with 2M hydrochloric acid. The whiteprecipitate was extracted with dichloromethane, dried over magnesiumsulphate, filtered and concentrated in vacuo to give a cream solid.Recrystallisation from an ethanol water mixture gave a cream colouredcrystalline solid (1.14g, 48%), meltinq point 72°-73° C.

NMR (270 MHz, CDCl₃ +d₆ DMSO): δ1.35 (6H, s), 1.50 (6H, s), 7.2-7.6 (4H,complex) (enolic proton broad--not observed)

IR (nujol) : 1720 (medium), 1680 (strong), 1560 (strong, broad), 1300(medium, broad), 1200 (weak), 1020 (medium), 770 (medium) cm⁻¹.

m.s. : M⁺ --Br 285.

Preparation 6 ##STR24##

The reaction was carried out under Argon. Cuprous cyanide (4.67g, 52.2mmol) and anhydrous sodium iodide (14.61g, 97 mmol) were stirred for 2minutes in anhydrous acetonitrile (100 ml). The resulting solution wasmixed with o-fluoro benzoyl chloride (7.73g, 48.7 mmol) whereupon anorange precipitate formed. The mixture was stirred for 30 minutes atroom temperature, filtered and concentrated in vacuo. The residue wastaken up in dichloromethane and the resultant precipitate was filteredoff.

Concentration of the filtrate under reduced pressure an orange oil.Distillation in Kugelrohr apparatus gave o-fluorobenzoyl cyanide as ayellow liquid (5.07g, 66%).

NMR (60 MHz, CDCl₃): δ7.2δ8.2 (4H, complex). IR (liquid film) : 2225(medium), 1680 (stronq), 1610 (strong), 1580 (medium), 750 (strong)cm⁻¹.

g.c. m.s. : M⁺ 149.

EXAMPLE 4

This Example illustrates the preparation of Compound No. 4 in Table I.

The tetramethylated triketone (ii) (1.19q, 6.54 mmol), o-fluorobenzoylcyanide (vi) (0.97g, 6.54 mmol) and anhydrous zinc chloride (0.98g, 7.19mmol) were combined in dry acetonitrile (10 ml). Triethylamine (1.09 ml,7.85 mmol) in acetonitrile (5 ml) was added slowly to the mixture withcooling to -10° C. The reaction was stirred at this temperature for 2hours, then allowed to warm to room temperature. After standing for 16hours the reaction mixture was poured into 2M hydrochloric acid (100 ml)and extracted with dichloromethane. The organic extracts were washedwith 10% sodium carbonate solution (3 ×50 ml) and the aqueous washingscombined and carefully acidified to give a white solid which wasfiltered off. This was purified on a column of silica using the solventsystem hexane, ether and acetic acid in a ratio of 50:50:2.Concentration in vacuo of the first component to come off the columnafforded an orange solid, which was recrystallised from a methanol watermixture to give yellow crystals (0.7g, 35%) melting point 69° -70° C.

NMR (90 MHz, CDCl₃) : δ1.4 (6H, s), 1.56 (6H, s), 6.9-7.6 (5H, complex),17.4 (1H, s).

IR (nujol) : 3500 (medium, 1720 (weak), 1680 (strong), 1620 (weak), 1560(medium, broad), 1220 (weak), 760 (medium) cm⁻¹.

m.s. : M⁺ 304.

Preparation 7 ##STR25##

The reaction was carried out under Argon. Cuprous cyanide (4.22g, 47mmol) and anhydrous sodium iodide (13.12g, 87 mmol) were stirred for 2minutes in anhydrous acetonitrile (100 ml). The resulting solution wasmixed with o-trifluoromethylbenzoyl chloride (9.16q, 44 mmol) whereuponan orange precipitate formed. The reaction mixture was stirred for 30minutes at room temperature, filtered and concentrated in vacuo. Theresidue was taken up in dichloromethane and the resultant precipitatewas filtered off. Concentration of the filtrate in vacuo qave an orangeoil which crystallised on standing.

Recrystallisation from 60°-80° C. b.p.t. petroleum ether qave ao-fluoromethylbenzoyl cyanide as pale yellow crystals (3.5g, 40%),melting point 41° C.

NMR 60 MHz, : δ7.27-8.37 (4H, complex). IR (nujol): 2225 (weak), 1700(stronq), 1600 (weak), 1580 (medium), 970 (strong) cm⁻¹.

g.c. m.s.: M+199

EXAMPLE 5

This Example illustrates the preparation of Compound No. 5 in Table I.

The tetramethylated triketone (ii) (1.13g, 6.21 mmol,),o-trifluoromethylbenzoyl cyanide (vi) (1.23q, 6.21 mmol) and anhydrouspowdered zinc chloride (0.93g, 6.83 mmol) were combined in dryacetonitrile (10 ml). Triethylamine (1.03 ml, 7.45 mmol) in dryacetonitrile (5 ml) was added slowly to the mixture with cooling to--10°C. The reaction mixture was then allowed to reach room temperature thenheated under reflux for 4 hours. The reaction mixture was poured into 2Mhydrochloric acid (100 ml) and extracted with dichloromethane. Theorganic extracts were washed with 10% sodium carbonate solution (3×50ml) and the aqueous washings combined and acidified to give a whiteprecipitate. Extraction with dichloromethane, drying over magnesiumsulphate, filtration and concentration in vacuo qave an oily orangesolid. Trituration with 60°-80° C. b.p.t. petroleum ether, filtrationand concentration of the filtrate in vacuo gave a yellow oil which waspurified on a column of silica using the solvent system hexane, etherand acetic acid in the ratio 50:50:5. Concentration in vacuo of thefirst fraction to come off the column qave a yellow oil (0.60g, 27%).

NMR (400 MHz, CDC13) :δ1.3 (6H, s), 1.55 (6H, s), 7.2-7.9 (4H, complex)(enolic proton broad--not observed)

IR (liquid film) : 1725 (medium, 1680 (strong), 1560 (strong, broad),1320 (stronq), 760 (strong).

m.s. : M⁺ 354.

EXAMPLE 7

This Example illustrates the preparation of compound 6 in Table 1.

Sodium, (2.76g, 0.12 mol) was added to methanol (200 ml) slowly withstirring. Phlorobenzophenone (4.6g, 0.02 mol) was stirred into thesolution then methyliodide (17.4q, 0.12 mol) was added slowly and thereaction mixture heated under reflux for 4 hours. Excess methyl iodideand methanol were removed by concentration in vacuo to give a yellowsolid, which was dissolved in water, acidified with 2M HCl and extractedwith ether. The ethereal phase was washed with sodium sulphite and thesodium sulphite washings were then acidified with 2M HCl and taken up inether. The combined ether extracts were washed with water, dried overMqS04 and concentrated in vacuo to give oily orange needles, which wererecrystallised from ethanol/water to give pale yellow needles, 3.0g, 53%mpt. 71-72° C. ir (Nujol) 1725, 1680, 1600, 1280, 1160, 1040, 860, 840,770 cm⁻¹

Biological Data

The herbicidal activity of compound 6 was tested as follows:

The compound in the appropriate concentration was incorporated into a 4%emulsion of methyl cyclohexanone and a 0.4% blend of 3.6 parts Tween 20and 1 part Span 80. Tween 20 is a Trade Mark for a surface active agentcomprising a condensate of 20 molar proportions of ethylene oxide withsorbitan laurate. Span 80 is a Trade Mark for a surface-active agentcomprising sorbitan monoalaurate. Formulation was effected by dissolvingthe compound in the requisite amount of solvent/surfactant blend. Ifnecessary glass beads were added, the total liquid volume adjusted to 5ml with water and the mixture shaken to effect complete dissolution ofthe compound. The formulation so prepared, after removal of beads werenecessary, was then diluted to final spray volume (45 ml) with water).

The spray compositions so prepared were sprayed onto young pot plants(post-emergence test) at a rate equivalent to 1000 liters per heater.Damage to plants was assessed 13 days after spraying by comparison withuntreated plants, on a scale of 0 to 5 where 0 is 0-10% damage, 1 is 11to 25% damage, 2 is 26-50% damage, 3 is 51-80% damage, 4 is 81-95%damage and 5 is 96-100% damage.

In a test carried out to detect pre-emergence herbicidal activity, seedsof the test species were placed on the surface of plastic trays ofcompost and sprayed with the compositions at the rate of 1000 liters perhectare. The seeds were then covered with further compost. 20 Days afterspraying, the seedlings in the sprayed plastic trays were compared withthe seedlings in unsprayed control trays, the damage being assessed onthe same scale of 0 to 5.

The results of the tests are given in Table II below.

                                      TABLE II                                    __________________________________________________________________________            RATE OF  PRE- OR                                                      COMPOUND                                                                              APPLICATION                                                                            POST-EMERGENCE                                                                            TEST PLANTS (see Table III)                      NO.     kg/ha    APPLICATION Sb                                                                              Rp                                                                              Ct                                                                              Sy                                                                              Mz Ww Rc                                                                              Bd                                                                              Ip                                                                              Am Pi                                                                              Ca                      __________________________________________________________________________    6       4        Pre         5 4 1 2 0  0  0 2 1 0  0 4                                        Post        3 4 0 3 3  3  3 2 3 1  2 3                       __________________________________________________________________________            RATE OF  PRE- OR                                                      COMPOUND                                                                              APPLICATION                                                                            POST-EMERGENCE                                                                            TEST PLANTS (see Table III)                      NO.     kg/ha    APPLICATION Ga                                                                              Xa                                                                              Ab                                                                              Co                                                                              Av Dg Al                                                                              St                                                                              Ec                                                                              Sh Ag                                                                              Cn                      __________________________________________________________________________    6       4        Pre         0 0 5 2 0  4  0 3 3 4  0 3                                        Post        2 2 4 0 2  4  0 3 3 1  2 3                       __________________________________________________________________________

TABLE II

Abbreviations used for Test Plants

Sb--Sugar beet

Rp--Rape

Ct--Cotton

Sy--Soybean

Mz--Maize

Ww--Winder wheat

Rc--Rice

Bd--Bidens pilosa

Ip--Ipomoea purpurea

Am--Amarunthus retroflexus

Pi--Polygonum aviculare

Ca--Chenopodium alubum

Ga--Galium aparine

Xa--Xanthium spinsum

Xs--Xanthium strumarium

Ab--Abutilon theophrasti

Co--Cassia obtusifolia

Av--Avena fatua

Dg--Digitaria sanquinalis

Al--Alopercurus myosuroides

St--Setaria viridio

Ec--Echinchloa crus-galli

Sh--Sorqhum halepense

Ag--Agropyron repens

Cn--Cypenus rotundus

I claim:
 1. A process for preparing a compound of formula (I) ##STR26##or a salt, acylate or sulphonate derivative thereof; wherein R' is anoptionally substituted aryl group in which the optional substitution isup to three groups selected from halogen; C₁₋₄ alkyl; C₁₋₄ alkoxy; halo(C₁₋₄) alkoxy; cyano; nitro; C₁₋₄ haloalkyl; R⁷ SO_(n) -where n is 0, 1or 2 and R⁷ is C₁₋₄ alkyl or C₁₋₄ alkyl substituted with halogen orcyano, phenyl or benzyl; NR⁸ R⁹ where R⁸ and R⁹ are independentlyhydrogen or C₁₋₄ alkyl; R¹⁰ CO- where R¹⁰ is C₁₋₄ alkyl or C₁₋₄ alkoxy;or SO₂ NR⁸ R⁹ where R⁸ and R⁹ are as defined above, R², R³,R⁴, And R⁵are selected from hydrogen, C₁₋₄ alkyl, C₁₋₄ alkanoyl or --CO₂ R^(a)wherein R^(a) is C₁₋₄ alkyl or R² and R³ or R⁴ and R⁵ together with thecarbon atom to which they are attached form a C₃₋₆ cycloalkyl ring,provided that at least R² and R³ or R⁴ and R⁵ are not both hydrogen andthat not more than two of R², R³, R⁴ and R⁵ are C₁₋₄ alkanoyl or --CO₂R^(a) ; which process comprises reacting a compound of formula (VI)##STR27## with a compound of formula (X) ##STR28## wherein R¹ is ashereinbefore defined, in the presence of a Lewis acid.